Justice of the Peace Brad Burnett has ordered an autopsy. Investigators told KFDM-TV that heat may have been a factor, with temperatures Monday topping 90 degrees.
Shoemaker's vehicle was found Monday night at the aircraft field near Nederland, about 10 hours after he told a fellow Labelle Fannett volunteer firefighter that he was going to check out a swampy area.
The remote-controlled plane, missing since Sunday, has not been located.
